The invention provides an electric energy meter protection characteristic optimization method and device based on transformer improvement. The method comprises the following steps of: constructing a circuit simulation model of an electric energy meter power loop and a thermal simulation model of an electric energy meter; randomly selecting a plurality of component parameter combinations and substituting the component parameter combinations into each circuit simulation model; determining the groups of voltage values and current values at each component, substituting the components into the thermal simulation model of the electric energy meter, and determining a virtual thermal simulation model; selecting the grades of silicon steel sheets, selecting the first loss values in a loss range corresponding to calibrated iron core parameters of the silicon steel sheets, obtaining the first temperature values according to the virtual thermal simulation model, and fitting to determine a functional relationship; selecting the iron core parameters in an iron core parameter distribution range of the silicon steel sheets, determining a corresponding second loss value, determining a correspondingsecond temperature value according to the functional relationship, carrying out distribution fitting on the second temperature value, and determining a probability density function corresponding to each silicon steel sheet; determining the error protection probability corresponding to each silicon steel sheet and the optimal silicon steel sheet.